Exemplo n.º 1
0
def tri(N, M=None, k=0, dtype=float):
    """ returns a N-by-M array where all the diagonals starting from
        lower left corner up to the k-th are all ones.
    """
    if M is None: M = N
    m = greater_equal(subtract.outer(arange(N), arange(M)),-k)
    return m.astype(dtype)
Exemplo n.º 2
0
def fix(x, out=None):
    """
    Round to nearest integer towards zero.

    Round an array of floats element-wise to nearest integer towards zero.
    The rounded values are returned as floats.

    Parameters
    ----------
    x : array_like
        An array of floats to be rounded
    out : ndarray, optional
        A location into which the result is stored. If provided, it must have
        a shape that the input broadcasts to. If not provided or None, a
        freshly-allocated array is returned.

    Returns
    -------
    out : ndarray of floats
        A float array with the same dimensions as the input.
        If second argument is not supplied then a float array is returned
        with the rounded values.

        If a second argument is supplied the result is stored there.
        The return value `out` is then a reference to that array.

    See Also
    --------
    trunc, floor, ceil
    around : Round to given number of decimals

    Examples
    --------
    >>> np.fix(3.14)
    3.0
    >>> np.fix(3)
    3.0
    >>> np.fix([2.1, 2.9, -2.1, -2.9])
    array([ 2.,  2., -2., -2.])

    """
    # promote back to an array if flattened
    res = nx.asanyarray(nx.ceil(x, out=out))
    res = nx.floor(x, out=res, where=nx.greater_equal(x, 0))

    # when no out argument is passed and no subclasses are involved, flatten
    # scalars
    if out is None and type(res) is nx.ndarray:
        res = res[()]
    return res
Exemplo n.º 3
0
def fix(x, out=None):
    """
    Round to nearest integer towards zero.

    Round an array of floats element-wise to nearest integer towards zero.
    The rounded values are returned as floats.

    Parameters
    ----------
    x : array_like
        An array of floats to be rounded
    y : ndarray, optional
        Output array

    Returns
    -------
    out : ndarray of floats
        The array of rounded numbers

    See Also
    --------
    trunc, floor, ceil
    around : Round to given number of decimals

    Examples
    --------
    >>> np.fix(3.14)
    3.0
    >>> np.fix(3)
    3.0
    >>> np.fix([2.1, 2.9, -2.1, -2.9])
    array([ 2.,  2., -2., -2.])

    """
    # promote back to an array if flattened
    res = nx.asanyarray(nx.ceil(x, out=out))
    res = nx.floor(x, out=res, where=nx.greater_equal(x, 0))

    # when no out argument is passed and no subclasses are involved, flatten
    # scalars
    if out is None and type(res) is nx.ndarray:
        res = res[()]
    return res
Exemplo n.º 4
0
def fix(x, out=None):
    """
    Round to nearest integer towards zero.

    Round an array of floats element-wise to nearest integer towards zero.
    The rounded values are returned as floats.

    Parameters
    ----------
    x : array_like
        An array of floats to be rounded
    y : ndarray, optional
        Output array

    Returns
    -------
    out : ndarray of floats
        The array of rounded numbers

    See Also
    --------
    trunc, floor, ceil
    around : Round to given number of decimals

    Examples
    --------
    >>> np.fix(3.14)
    3.0
    >>> np.fix(3)
    3.0
    >>> np.fix([2.1, 2.9, -2.1, -2.9])
    array([ 2.,  2., -2., -2.])

    """
    # promote back to an array if flattened
    res = nx.asanyarray(nx.ceil(x, out=out))
    res = nx.floor(x, out=res, where=nx.greater_equal(x, 0))

    # when no out argument is passed and no subclasses are involved, flatten
    # scalars
    if out is None and type(res) is nx.ndarray:
        res = res[()]
    return res
Exemplo n.º 5
0
def tri(N, M=None, k=0, dtype=float):
    """
    An array with ones at and below the given diagonal and zeros elsewhere.

    Parameters
    ----------
    N : int
        Number of rows in the array.
    M : int, optional
        Number of columns in the array.
        By default, `M` is taken equal to `N`.
    k : int, optional
        The sub-diagonal at and below which the array is filled.
        `k` = 0 is the main diagonal, while `k` < 0 is below it,
        and `k` > 0 is above.  The default is 0.
    dtype : dtype, optional
        Data type of the returned array.  The default is float.

    Returns
    -------
    tri : ndarray of shape (N, M)
        Array with its lower triangle filled with ones and zero elsewhere;
        in other words ``T[i,j] == 1`` for ``i <= j + k``, 0 otherwise.

    Examples
    --------
    >>> np.tri(3, 5, 2, dtype=int)
    array([[1, 1, 1, 0, 0],
           [1, 1, 1, 1, 0],
           [1, 1, 1, 1, 1]])

    >>> np.tri(3, 5, -1)
    array([[ 0.,  0.,  0.,  0.,  0.],
           [ 1.,  0.,  0.,  0.,  0.],
           [ 1.,  1.,  0.,  0.,  0.]])

    """
    if M is None:
        M = N
    m = greater_equal(subtract.outer(arange(N), arange(M)),-k)
    return m.astype(dtype)